leavenworth



.s. H. LEAVENWORTH. METAL TUBE.

Patented July 14, 1896.

[NI/ENTER U TTED STATES PATENT FFICF'E.

SETH H. LEAVENTVORTH, OF CINCINNATI, OHIO, ASSIGNOR OF ON E-HALF TO JOSEPH T. I'IOMAN, OF SAME PLACE.

METAL TUBE.

SPECIFICATION forming part of Letters Patent No. 563,932, dated July 14, 1896.

Application filed May 11, 1896. Serial No 590,998. (No model.)

To all whom it may concern.-

Be it known that I, SETH H. LEAVENWORTH, a citizen of the United States, and a resident of Cincinnati, in the county of Hamilton and State of Ohio, have invented. certain new and useful Improvements in Brazed Metal Tubing, of which the following is a specification.

The object of my invention is to produce light, strong, brazed tubing, especially adapted for bicycle-frames, which, when finished, will be practically as strong as the more expensive seamless tubing now employed for the same purpose.

The invention consists, essentially, in forming a blank of light sheet metal, preferably steel, of sufficient width to form a double fold, and having locking-tenons upon each end to lock into perforations in the body of the blank when the blank is folded to form the tube, the interlocking tenons overlapping upon each side of the joint to give strength to the tube and prevent the solder from passing through to the inside of the tube under the brazing process.

The invention will be first fully described in connection with the accompanying drawin gs, and will then'be particularly referred to and pointed out in the claims.

Referring to the drawings, in which like parts are indicated by similar reference-letters wherever they occur throughout the various views, Figure 1 isa plan view of a section of the blank from which my tube is to be formed. Fig. 2 is a View, partly in longitudinal elevation and partly in broken section, of the rolled tube. Fig. 3 is a transverse section of the completed tube, taken between the locking-tenons upon line a: a; of Fig. 2. Fig. 4 is a transverse sectional view taken through the locking-tenons upon the line y y of Fig.

2. Fig. 5 is a detail view in perspective, upon a greatly-enlarged scale, showing one part of the blank folded in and the tenons interlocked in the perforations in the blank, and the opposite end partially folded around preparatory to forcing the opposite tenon into its interlocking mortise. v

The blank A is formed from a rolled sheet of metal, of one-half the thickness of the tube to be formed, but of a width to permit the double fold shown in the subsequent figures,

plus the tenons on each edge and the angle formed centrally through the perforations which look the tenon-heads, and of the desired length, usually about four feet. This blank has a series of locking-tenons a and a upon its edges opposite each other, and in the same plane between the tenons a and a, a row of perforations which are contracted at their side walls and flare in opposite directions from there to their ends, each half of the perforation being counter to the tenons upon the opposite edge of the blank. The blank has an angular bend at which is parallel to the edges of the blank and in a plane centrally through the perforations. The angles aform shoulders upon each side of the blank against which their recessed edges a abut when the blank is rolled into the form of a tube, as clearly seen in Figs. 3 and 5. The angle a? may be formed before the blank is rolled or in the process of rolling, as may be most desirable, but when formed it will be seen that looking or dovetailed mortises a and a are upon opposite sides of it.

Then the blank is rolled to form a tube, the half A is folded over the tenons a until the tenons lock into their mortise C0 The rolling process being continued, the half of the blank A is rolled around the part A and its tenons a forced into the mortise The recesses a in the part A abut against the inner edge of the angle a while the recesses in the part A abut against the outer edge of said angle, the locking-heads a underlapping the part A While the dovetailed heads a overlap the part A. While in this locked position the joints are brazed, the solder under the action of the blow-pipe flowing freely through the edges of the joints, but none of it being wasted by passing through to the opposite side. After the tube is brazed, it may be completed by drawing, or .in any wellknown manner, in order to give -it the proper finish.

I have shown in the drawings the lockingtenons arranged in the same transverse plane, and the double-locking perforations or mortises arranged in the same plane,one-half upon each side of the longitudinal center or angle in the blanks; but it is obvious that the lockingtenons upon one edge may be placed opposite the recesses upon the opposite edge, in which case single-locking inortises or perforations will be formed alternately upon opposite sides of the longitudinal center or angle (1 to receive the tenons instead of the double niortises; but the form as shown is the stronger and requires less labor and care; but in each case the blank will form a tube with walls of uniform thickness; that is, without ribs or projections upon either the inner or outer surfaces. I have also shown substantially dovetailed locking-heads and corresponding mortises or perforations, but with the corners rounded to avoid sharp angles, which would weaken the punch or dies for stamping the blank out; but it is obvious that the regular dovetailed tenon or any interlocking tenon might be substituted for the one shown, and it is also obvious that many slight mechanical changes may be made without departing from the spirit or scope of my invention.

That I claim as new, and desire to secure by Letters Patent, is-

1. The hereinbefore-deseribed blank for forming sheet-metal tubes, having upon its opposite longitudinal edges locking-tenons and counter perforations upon opposite sides of the longitudinal center of said blank to re ceive the locking-tenons when the blank is folded to form a double-walled tube, substantially as shown and described.

2. The hereinbefore-described blank for forming sheet-metal tubes having upon its opposite longitudinal edges locking-tenons, counter perforations upon opposite sides of the longitudinal center of said blank to receive the locking-tenons, and an angular olfset between the locking-perforations against which the recessed edges of the blank abut when folded to form a double-walled tube, substantially as shown and described.

3. The blank for forming sheet-metal tubes, having upon its opposite edges locking-tenons in the same transverse plane, doublelocking nlortises one-half upon each side of the longitudinal center of the blank to receive both of the opposite locking-tenons when the blank is folded into a tube.

4:. The tube hereinbefore deseribed,havin g double wall of uniform thickness, lockingtenons upon its opposite edges, an angular offset against which the edge of the recesses between the tenons abuts, and inortises or perforations upon opposite sides of said offset to receive the tenons and form a locking-joint for the tube, as a new article of in anufaeture.

SETH II. LEAVENWORTII.

\Vitnesses:

JosnrH T. HOMAN, Gno. J. 1\1'[URRAY. 

